[PATCH v10 0/6] rust: reduce `as` casts, enable related lints

[Tamir Duberstein <tamird@gmail.com>]

This started with a patch that enabled `clippy::ptr_as_ptr`. Benno
Lossin suggested I also look into `clippy::ptr_cast_constness` and I
discovered `clippy::as_ptr_cast_mut`. This series now enables all 3
lints. It also enables `clippy::as_underscore` which ensures other
pointer casts weren't missed.

As a later addition, `clippy::cast_lossless` and `clippy::ref_as_ptr`
are also enabled.

This series depends on "rust: retain pointer mut-ness in
`container_of!`"[1].

Link: https://lore.kernel.org/all/20250409-container-of-mutness-v1-1-64f472b94534@gmail.com/ [1]

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Changes in v10:
- Move fragment from "rust: enable `clippy::ptr_cast_constness` lint" to
  "rust: enable `clippy::ptr_as_ptr` lint". (Boqun Feng)
- Replace `(...).into()` with `T::from(...)` where the destination type
  isn't obvious in "rust: enable `clippy::cast_lossless` lint". (Boqun
  Feng)
- Link to v9: https://lore.kernel.org/r/20250416-ptr-as-ptr-v9-0-18ec29b1b1f3@gmail.com

Changes in v9:
- Replace ref-to-ptr coercion using `let` bindings with
  `core::ptr::from_{ref,mut}`. (Boqun Feng).
- Link to v8: https://lore.kernel.org/r/20250409-ptr-as-ptr-v8-0-3738061534ef@gmail.com

Changes in v8:
- Use coercion to go ref -> ptr.
- rustfmt.
- Rebase on v6.15-rc1.
- Extract first commit to its own series as it is shared with other
  series.
- Link to v7: https://lore.kernel.org/r/20250325-ptr-as-ptr-v7-0-87ab452147b9@gmail.com

Changes in v7:
- Add patch to enable `clippy::ref_as_ptr`.
- Link to v6: https://lore.kernel.org/r/20250324-ptr-as-ptr-v6-0-49d1b7fd4290@gmail.com

Changes in v6:
- Drop strict provenance patch.
- Fix URLs in doc comments.
- Add patch to enable `clippy::cast_lossless`.
- Rebase on rust-next.
- Link to v5: https://lore.kernel.org/r/20250317-ptr-as-ptr-v5-0-5b5f21fa230a@gmail.com

Changes in v5:
- Use `pointer::addr` in OF. (Boqun Feng)
- Add documentation on stubs. (Benno Lossin)
- Mark stubs `#[inline]`.
- Pick up Alice's RB on a shared commit from
  https://lore.kernel.org/all/Z9f-3Aj3_FWBZRrm@google.com/.
- Link to v4: https://lore.kernel.org/r/20250315-ptr-as-ptr-v4-0-b2d72c14dc26@gmail.com

Changes in v4:
- Add missing SoB. (Benno Lossin)
- Use `without_provenance_mut` in alloc. (Boqun Feng)
- Limit strict provenance lints to the `kernel` crate to avoid complex
  logic in the build system. This can be revisited on MSRV >= 1.84.0.
- Rebase on rust-next.
- Link to v3: https://lore.kernel.org/r/20250314-ptr-as-ptr-v3-0-e7ba61048f4a@gmail.com

Changes in v3:
- Fixed clippy warning in rust/kernel/firmware.rs. (kernel test robot)
  Link: https://lore.kernel.org/all/202503120332.YTCpFEvv-lkp@intel.com/
- s/as u64/as bindings::phys_addr_t/g. (Benno Lossin)
- Use strict provenance APIs and enable lints. (Benno Lossin)
- Link to v2: https://lore.kernel.org/r/20250309-ptr-as-ptr-v2-0-25d60ad922b7@gmail.com

Changes in v2:
- Fixed typo in first commit message.
- Added additional patches, converted to series.
- Link to v1: https://lore.kernel.org/r/20250307-ptr-as-ptr-v1-1-582d06514c98@gmail.com

---
Tamir Duberstein (6):
      rust: enable `clippy::ptr_as_ptr` lint
      rust: enable `clippy::ptr_cast_constness` lint
      rust: enable `clippy::as_ptr_cast_mut` lint
      rust: enable `clippy::as_underscore` lint
      rust: enable `clippy::cast_lossless` lint
      rust: enable `clippy::ref_as_ptr` lint

 Makefile                               |  6 ++++++
 drivers/gpu/drm/drm_panic_qr.rs        |  2 +-
 rust/bindings/lib.rs                   |  3 +++
 rust/kernel/alloc/allocator_test.rs    |  2 +-
 rust/kernel/alloc/kvec.rs              |  4 ++--
 rust/kernel/block/mq/operations.rs     |  2 +-
 rust/kernel/block/mq/request.rs        |  6 +++---
 rust/kernel/device.rs                  |  4 ++--
 rust/kernel/device_id.rs               |  4 ++--
 rust/kernel/devres.rs                  | 19 ++++++++++---------
 rust/kernel/dma.rs                     |  6 +++---
 rust/kernel/error.rs                   |  2 +-
 rust/kernel/firmware.rs                |  3 ++-
 rust/kernel/fs/file.rs                 |  2 +-
 rust/kernel/io.rs                      | 18 +++++++++---------
 rust/kernel/kunit.rs                   | 11 +++++++----
 rust/kernel/list/impl_list_item_mod.rs |  2 +-
 rust/kernel/miscdevice.rs              |  2 +-
 rust/kernel/net/phy.rs                 |  4 ++--
 rust/kernel/of.rs                      |  6 +++---
 rust/kernel/pci.rs                     | 11 +++++++----
 rust/kernel/platform.rs                |  4 +++-
 rust/kernel/print.rs                   |  6 +++---
 rust/kernel/seq_file.rs                |  2 +-
 rust/kernel/str.rs                     | 14 +++++++-------
 rust/kernel/sync/poll.rs               |  2 +-
 rust/kernel/time/hrtimer/pin.rs        |  2 +-
 rust/kernel/time/hrtimer/pin_mut.rs    |  2 +-
 rust/kernel/uaccess.rs                 |  4 ++--
 rust/kernel/workqueue.rs               | 12 ++++++------
 rust/uapi/lib.rs                       |  3 +++
 31 files changed, 96 insertions(+), 74 deletions(-)
---
base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8
change-id: 20250307-ptr-as-ptr-21b1867fc4d4
prerequisite-change-id: 20250409-container-of-mutness-b153dab4388d:v1
prerequisite-patch-id: 53d5889db599267f87642bb0ae3063c29bc24863

Best regards,
-- 
Tamir Duberstein <tamird@gmail.com>